Curable silicone composition, encapsulant and optical semiconductor device

Abstract

A Curable Silicone Composition, Encapsulant And Optical Semiconductor Device provides a curable silicone composition having excellent storage stability at room temperature. A curable silicone composition having (A) a resinous alkenyl group-containing organopolysiloxane including at least two alkenyl groups per molecule and at least one siloxane unit represented by SiO 4/2 ; (B) an organohydrogenpolysiloxane having at least two silicon atom-bonded hydrogen atoms in one molecule; (C) an alkyne group-containing compound; and (D) a curing catalyst, wherein the content of the resinous alkenyl group-containing organopolysiloxane (A) is 20 mass % or more based on the total mass of the organopolysiloxane components.

What is claimed is: 
     
       1. A curable silicone composition comprising:
 (A) a resinous alkenyl group-containing organopolysiloxane including at least two alkenyl groups per molecule and at least one siloxane unit represented by SiO 4/2  wherein the component (A) is represented by the following average unit formula(I);
   (R 1   3 SiO 1/2 ) a (R 1   2 SiO 2/2 ) b (R 1 SiO 3/2 ) c (SiO 4/2 ) d (XO 1/2 ) e    (I)
 
 
 wherein
 R 1  may be the same or different and each is independently selected from the group consisting of C1-12 alkyl groups and C2-12 alkenyl groups, where at least two R 1  in one molecule are alkenyl groups, 0<a<1, 0<b<1, 0<c<0.9, 0<d<1, 0<e<0.4, and a+b+c+d=1.0; and 
 X is a hydrogen atom or an alkyl group; 
 
 (B) an organohydrogenpolysiloxane having at least two silicon atom-bonded hydrogen atoms in one molecule wherein the organohydrogenpolysiloxane is a linear organohydrogenpolysiloxane having silicon atom-bonded hydrogen atoms on a side chain; 
 (C) an alkyne group-containing compound that is an alkyne group-containing silane selected from the group consisting of methyl-tris(1,1-dimethyl-2-butynoxy)silane, methyl-tris(3-methyl-1-butyn-3-oxy)silane, vinyl-tris (1,1-dimethyl-2-butynoxy)silane, and combinations thereof; and 
 (D) a curing catalyst, wherein the content of the resinous alkenyl group-containing organopolysiloxane (A) is 20 mass % or more based on the total mass of the organopolysiloxanes. 
 
     
     
       2. The curable silicone composition as claimed in  claim 1 , further including a linear alkenyl group-containing organopolysiloxane. 
     
     
       3. The curable silicone composition as claimed in  claim 1 , including at least two linear alkenyl group-containing organopolysiloxanes. 
     
     
       4. The curable silicone composition as claimed in  claim 1 , wherein the curing catalyst (D) is a platinum-based catalyst and includes from 0.01 ppm to 10 ppm of platinum atoms with respect to the total mass of the curable silicone composition. 
     
     
       5. The curable silicone composition as claimed in  claim 4 , wherein the molar ratio (H/Vi) of the alkenyl groups and hydrogen atoms derived from the organopolysiloxanes is from 0.8 to 3.0. 
     
     
       6. An encapsulant comprising the curable silicone composition as claimed in  claim 1 . 
     
     
       7. An optical semiconductor device that is equipped with a cured product of the encapsulant as claimed in  claim 6 . 
     
     
       8. The curable silicone composition as claimed in  claim 1 , that is free of 1-ethynyl-1-cyclohexanol. 
     
     
       9. The curable silicone composition as claimed in  claim 8 , wherein the (A) resinous alkenyl group-containing organopolysiloxane is represented by average unit formula:
   (ViMe 2 SiO 1/2 ) 10 (Me 3 SiO 1/2 ) 40 (SiO 4/2 ) 50 . 
 
     
     
       10. The curable silicone composition as claimed in  claim 9 , further including
 a first linear alkenyl group-containing organopolysiloxane represented by average structural formula:
   ViMe 2 SiO(Me 2 SiO) 200 SiMe 2 Vi; 
 
 
       and
 a second linear alkenyl group-containing organopolysiloxane represented by average structural formula:
   ViMe 2 SiO(Me 2 SiO) 850 SiMe 2 Vi. 
 
 
     
     
       11. The curable silicone composition as claimed in  claim 10 , wherein the (B) organohydrogenpolysiloxane is a linear organohydrogenpolysiloxane represented by average structural formula:
   Me 3 SiO(HMeSiO) 50 SiMe 3 . 
 
     
     
       12. The curable silicone composition as claimed in  claim 11 , wherein the (C) alkyne group-containing compound is methyl-tris(3-methyl-1-butyn-3-oxy)silane and is present in an amount of from about 0.015 to about 0.1 parts by weight based on 100 parts by weight of the organopolysiloxane components. 
     
     
       13. The curable silicone composition as claimed in  claim 12  having a pot life of at least about 600 days measured under conditions of 25° C./50% RH. 
     
     
       14. The curable silicone composition as claimed in  claim 1 ,
 wherein the (A) resinous alkenyl group-containing organopolysiloxane is represented by average unit formula:
   (ViMe 2 SiO 1/2 ) 10 (Me 3 SiO 1/2 ) 40 (SiO 4/2 ) 50    
 
 
       and is present in an amount of from about 53 to about 56 weight precent based on a total weight of (A) and (B); and
 that is free of 1-ethynyl-1-cyclohexanol. 
 
     
     
       15. The curable silicone composition as claimed in  claim 14 , further including
 a first linear alkenyl group-containing organopolysiloxane represented by average structural formula:
   ViMe 2 SiO(Me 2 SiO) 200 SiMe 2 Vi 
 
 
       present in an amount of from about 28 to about 29 weight precent based on a total weight of (A) and (B); and
 a second linear alkenyl group-containing organopolysiloxane represented by average structural formula:
   ViMe 2 SiO(Me 2 SiO) 850 SiMe 2 Vi 
 
 
       present in an amount of from about 10 to about 11 weight precent based on a total weight of (A) and (B). 
     
     
       16. The curable silicone composition as claimed in  claim 15 ,
 wherein the (B) organohydrogenpolysiloxane is a linear organohydrogenpolysiloxane represented by average structural formula:
   Me 3 SiO(HMeSiO) 50 SiMe 3    
 
 
       present in an amount of from about 5 to about 9 weight precent based on a total weight of (A) and (B);
 wherein the (C) alkyne group-containing compound is methyl-tris(3-methyl-1-butyn-3-oxy)silane and is present in an amount of from about 0.015 to about 0.1 parts by weight based on 100 parts by weight of the organopolysiloxane components; and 
 wherein the composition has a pot life of at least about 600 days measured under conditions of 25° C./50% RH. 
 
     
     
       17. The curable silicone composition as claimed in  claim 1 , that is free of 1-ethynyl-1-cyclohexanol and wherein the (C) alkyne group-containing compound is methyl-tris(3-methyl-1-butyn-3-oxy)silane and is present in an amount of from about 0.015 to about 0.1 parts by weight based on 100 parts by weight of the organopolysiloxane components. 
     
     
       18. A curable silicone composition comprising:
 (A) a resinous alkenyl group-containing organopolysiloxane represented by average unit formula:
   (ViMe 2 SiO 1/2 ) 10 (Me 3 SiO 1/2 ) 40 (SiO 4/2 ) 50 ; 
 
 a first linear alkenyl group-containing organopolysiloxane represented by average structural formula:
   ViMe 2 SiO(Me 2 SiO) 200 SiMe 2 Vi; 
 
 
       and
 a second linear alkenyl group-containing organopolysiloxane represented by average structural formula:
   ViMe 2 SiO(Me 2 SiO) 850 SiMe 2 Vi; 
 
 (B) a linear organohydrogenpolysiloxane represented by average structural formula:
   Me 3 SiO(HMeSiO) 50 SiMe 3 ; 
 
 (C) an alkyne group-containing compound that is methyl-tris(3-methyl-1-butyn-3-oxy)silane present in an amount of from about 0.015 to about 0.1 parts by weight based on 100 parts by weight of the organopolysiloxane components; and 
 (D) a curing catalyst, wherein the content of the resinous alkenyl group-containing organopolysiloxane (A) is 20 mass % or more based on the total mass of the organopolysiloxanes; 
 wherein the composition is free of 1-ethynyl-1-cyclohexanol; 
 wherein the composition has a pot life of at least about 600 days measured under conditions of 25° C./50% RH; and 
 wherein the molar ratio (H/Vi) of the alkenyl groups and hydrogen atoms derived from the organopolysiloxanes is from about 1 to about 2.